In-app purchase:
You can be a premium user and get more features through auto-renewable subscription:

1 Month: $11.99
1 Year: $35.99

- Your iTunes account will be charged for subscription renewal within 24-hours prior to the end of the current period.
- You can turn off the auto-renew at any time (24-hours before the end of the current period), but No cancellation for the current subscription period.